This is a technical document that has definitions and acronyms of common terms that are used within the context of Half-Life related game development. This is not a tutorial or a "How-to" document; its focus is to inform you what something is, not how to use it. For this, it is suggested that you consult a relevant resource or article here on the VERC Collective or elsewhere (although there are many instances where definitions will link you to an appropriate internet resource for more information).

Each definition has the following format:

1. (Foo) The name of the term.
2. (Numbers) Some terms may have multiple symbolic meanings. These are split up into separate entries.
3. (Context) Indicates the context of the particular meaning. eg. Mapping, Programming, Geometry...
4. (Numbered item)The definition itself.
5. (See also) A definition may also have relevant information available elsewhere. If you want to know more on a particular topic, then use these links provided.

Tips:

• Use your browsers Find feature to find a specific word or phrase.
• Pressing home on your keyboard will return you to the top of the page.

Note: The majority of this article is written by a single person. I have devoted a fair amount of effort to validating what is written here, but there are are possibly inaccuracies present, even if it does benefit from the eagle eye verification of the collective editors. While I don't claim to be ultimate authority on Half-Life game development, the article itself does, as it forms a point of reference. Therefore, if you do find any inaccuracies, please jump about and attract some attention, so the article may be amended.

Acronyms

API

Application Programming Interface (Programming)

BBE

Brush Based Entity (Mapping)

• See: Brush Based Entity.

BSP

Binary Space Parition (Engine)

• See: Binary Space Partition.

CS

Counter-Strike (Half-Life)
A popular multi-player based modification for Half-life.

• See Also: Counter-Strike homepage.

CSG

Constructive Solid Geometry (Mapping)

• See: Constructive Solid Geometry.

CTF

Capture The Flag (Half-Life)
A specific multiplayer gameplay style.

CMY

Cyan Magenta Yellow
Subtractive Color Model, Made up of Cyan Magenta and Yellow. Used in systems which absorb light (eg. printed material, etc).

CMYK

Cyan Magenta Yellow K
Subtractive Color Model, Made up of Cyan Magenta and Yellow with K darkness. Used in systems which absorb light (eg. printed material, etc).

D3D

Direct 3D (Engine)

• See: Direct3D.

DLL

Dynamic Link Library (Programming)

DM

Deathmatch
A specific type of gameplay, where opponents battle online against each other for Frags.

DMC

DeathMatch Classic (Half-Life)
A modification for Half-Life by Valve Software.

FPS

1. Frames Per Second (Engine)
2. First Person Shooter

FOV

Field Of View (Engine)

HL

Half-Life
Oh, come on.

HOM

Hall of Mirrors (Engine)

• See: Hall of Mirrors.

HPW

High Ping Whiner

HSL

Hue Saturation Luminance

HUD

Heads Up Display

IDE

Intergrated Development Environment (Programming)

LAN

Local Area Network

LMB

Left Mouse Button

LPB

Low Ping Bastard

MMB

Middle Mouse Button

MP

Multiplayer
Gameplay involving other human players either online or over network.

OP4

Opposing Force (Half-Life)
A commercial modification for Half-Life by Gearbox Software.

• See Also: Gearbox Software homepage.

OGL

Open Graphics Library (Engine)

• See: OpenGL

PBE

Point Based Entity

• See: Point Based Entity.

PC

1. Personal Computer

2. Partial Conversion

RGB

Red Green Blue
Additive Color Model created by combining Red Green and Blue. Used in luminous systems (such as monitors, etc.).

RGBA

Red Green Blue Alpha
Additive Color Model created by combining Red Green and Blue with Alpha brightness. Used in luminous systems (such as monitors, etc.).

RMB

Right Mouse Button

SP

Singleplayer

TC

Total Conversion

TFC

Team Fortress Classic (Half-Life)
A modification for Half-Life by Valve Software.

VERC

Valve Editing Resource Center

• See: Valve Editing Resource Center homepage.

VIS

Visible Information Set (Engine)

• See: Visible Information Set.

VHE

Valve Hammer Editor (Mapping)
A map making tool released by Valve.

• See Also: Valve Hammer Editor 3.4.

WC

Worldcraft (Mapping)
A map making tool released by Valve. Later renamed to Valve Hammer Editor, the Worldcraft series of editors are no longer supported.

• See Also: Valve Hammer Editor 3.4.

ZHLT

Zoners Half-Life Compile Tools (Mapping)
A set of map compilation tools specifically for Half-Life maps. They replace the deprecated Quake compile tools (QCSG, QBSP, etc) that are supplied with the VHE.

• See Also: Zoner's Half-Life Compile Tools.
• See Also: ZHLT Custom Build.

---

Terms

Argument

[popupid: argument]

1.
(Map Compilation) A commandline parameter passed to a particluar tool in order to modify
a setting within that tool when it is executed. Usually, commandline parameters/arguments
are handled by the copilation controller, but in the case of manual or batchfile compilations,
the mapper must manually specify program arguments though the commandline. An example of an
argument for the hlcsg.exe program in ZHLT (Link: _ZHLT) is -estimate .

Binary Space Partition

[popupid: bsp]

1.
(Mapping) The name given to the second stage of the map compile process. It primarily involves the
subdvision of the player space within the map into Leaf (Link: #Leaf) s and Portals (Link: #Portal) .
Often abbreviated as BSP. In ZHLT (Link: #_ZHLT) , this process is performed by the hlbsp.exe program.

Bevel

[popupid: bevel]

1.
(Geometry) The process of performing a cut or division at any non-axial angle (ie. an angle
that is not a multiple of 90?).

Bitfield

[popupid: bitfield]

1.
(Mapping) A specific type of Entity (Link: #Entity) Keyvalue (Link: #Keyvalue) . Its
value is an integer sum that can be used to represent the state of around 16 individual boolean values.
To determine the value of this type of Keyvalue, the mapper should add up the individual values
of the options he wishes to enable.

Bounding Box

[popupid: bounding_box]

1.
(Engine) A 3D rectangular cuboid that is used to enclose the total space occupied by an object.

2.
(Worldcraft) The coloured rectangular box that is used to describe the presence of a
Point Based Entity (Link: #Point Based Entity) .

Brush

[popupid: brush]

1.
(Mapping) A primitive solid used to construct the map architecture with.
Because of the nature of the map file format which is used to store Brushes, all Brushes:

• Must be Convex (Link: #Convex) .
• Cannot contain Coplanar (Link: #Coplanar) faces.
• Must have all Vertex (Link: #Vertex) es within the Half-Life world grid limits of ?4096.

See Also: Map File Format (Link: index.php?go=map_format) .

Brush Based Entity

[popupid: bbe]

1.
(Engine) An Entity (Link: #Entity) which makes use of Brush (Link: #Brush) es to describe its physical presence within
the map. Brush Based Entities can be thought of as Point Based Entities (Link: #Point Based Entity)
with Brushes attached, which can be manipulated (as a group) by the parent Point Based Entity for appropriate effects
when the map is played.

Brush Model

1.
(Engine) A Brush Based Entity (Link: #Brush Based Entity) .

See Also: Brush Based Entity (Link: #Brush Based Entity) .

Carve

[popupid: carve]

1.
(Worldcraft) A subtractive geometric building tool integrated into the
Worldcraft/Valve Hammer Editor editor. It is accessible through:

• the right click menu
• the menu item Tools, Carve
• the keyboard shortcut Shift+Ctrl+C
• the toolbar button
  wc_toolbar_carve.gif

Taken directly from the Worldcraft help file:

In the editor, any solid can be used to carve a volume out of other solids.
For example, you can place a solid within the room's wall and tell Hammer to subtract the
solid from the wall -- effectively punching a hole right through the wall! This feature is
not limited to using cubic shapes as a carving tool: any solid -- cylinders, cubes and
wedges -- can be used to carve other solids.

See Also: Carving Responsibly (Link: index.php?doc=1026123232-54568900) .

Channel

[popupid: audio_channel]

1.
(Engine) A single stream of audio. Each stream can only play one sound at a time.
The engine uses several channels for separate purposes, all of which are mixed together
into a single stream (by either a software or hardware mixer) before being sent to the
audio hardware device.

Client

1.
(Engine) A particular mode of operation for the Half-Life engine. In client mode,
the engine connects to a game server and communicates with that server using a set protocol
in order for Half-Life to play over the Internet or Network with other players.

2.
(Engine) A specific DLL (Link: #_DLL) in the Half-Life modification API (Link: #_API) . The client DLL file contains
code that is specific to the client mode of engine operation and the modification itself.
The client DLL communicates with the Server (Link: #Server) DLL though the Half-Life
message API.

See Also: How To Make A Mod (Link: index.php?go=howto_mod) .

3.
(Half-Life) A player on a multiplayer game Server (Link: #Server) .

CLIP or Clip

1.
(Mapping) The name given to a special Texture (Link: #Texture) that, when applied to all
Side (Link: #Side) s of a Brush (Link: #Brush) , is used to make a Clip Brush (Link: #Clip Brush) .
It is included in the standard halflife.wad file.

2.
(Worldcraft) A tool that is used to split a Brush (Link: #Brush) into two parts along a Clip Plane (Link: #Clip Plane) ,
or remove a section of Brush defined by a Clip Plane.

Clip Brush

[popupid: clip_brush]

1.
(Mapping) A Brush (Link: #Brush) that has the CLIP (Link: #Clip) Texture (Link: #Texture)
on all Side (Link: #Side) s.
When the map is run though the Half-Life engine, the Brush blocks the player, but does not stop
projectiles and is not visible.

Clip Plane

1.
(Worldcraft) A plane that is positioned in the 2D views by the mapper where he wishes
the editor to perform the clip operation. By default, this is a bold white line.

2.
(Mapping) A Plane (Link: #Plane) created by a Side (Link: #Side) of a Clip Brush (Link: #Clip Brush) .

See Also: Clip Brush (Link: #Clip Brush) .

Clipnode

[popupid: clipnode]

1.
(Engine) A Surface (Link: #Surface) that is used to perform collision detection. In Half-Life, the
map compile process assigns Clipnodes to the Surfaces in the map which it determines
should behave solid when the map is run though the Half-Life engine.

Compare: Node (Link: #Node) .

Console

[popupid: console]

1.
(Engine) A text based method of communication between the player and
the Half-Life engine. If the console is enabled, it can be accessed in the game
by pressing the tilde key (~).

Constructive Solid Geometry

[popupid: csg]

1.
(Mapping) The name given to the first stage of the map compile process. This stage often
involves basic compilation operations such as initial surface subdivisions, texdata heap
validation and initial hull construction. Often abbreviated as CSG. In ZHLT (Link: #_ZHLT) ,
this process is performed by the hlcsg.exe program.

Cube

[popupid: cube]

1.
(Geometry) A solid composed of 6 side (Link: #Side) s, 12
edge (Link: #Edge) s and 8 vertex (Link: #Vertex) es. All six sides are square
and are equal in all respects with exception to spatial orientation.

Direct3D

1.
(Engine) A closed source proprietary graphics library API (Link: #_API) provided by Microsoft and used
by the Half-Life engine to render the Half-Life world if the 'Direct3D' rendermode is
chosen by the user.

See Also: Direct3D homepage (Link: ProgrammersGuide.asp) .
Compare: OpenGL (Link: #OpenGL) .

Decal

[popupid: decal]

1.
(Mapping) A static image that is placed onto a brush surface using the
infodecal (Link: index.php?ent=infodecal&game=hl) entity.
Often used for minor 2D surface detail such as bulletholes, blood, scorch marks, etc.

See Also: Half-Life Entity Guide: infodecal (Link: index.php?ent=infodecal&game=hl) .

Edge

[popupid: edge]

1.
(Geometry) A line in 3D space where two side (Link: #Side) s meet. At each end of
this line is a vertex (Link: #Vertex) .

Edict

[popupid: edict]

1.
(Engine) A block of memory space used by an entity. The Half-Life
engine ( which is primarly based on the Quake engine (Link: index.php?go=q1_or_q2) ) has a limited
number of Edicts that it may create and use.

Face

1.
(Geometry) A general term for a facade or Surface (Link: #Surface) . Brush (Link: #Brush) sides
are also Brush Faces.

Frag

1.
(Half-Life) A kill generated on an online/network multiplayer game.

2.
(Geometry) A fragment.

Fullbright

[popupid: fullbright]

1.
(Mapping) A condition where a map has no apparent lightmap (Link: #Lightmap) , and is therefore displayed
at maximum brightness when run through the Half-Life engine. This brightness is usually
the result of a map compilation error in which the radiosity process failed to run to completion
sucessfully, and no lightmap for the map was generated.

Gamma

1.
(Engine) The lighting scale applied to the video output from the engine. Raising
the gamma level usually results in a brighter, more luminous output at the expese of
contrast. Lowering the gamma level usually results in a darker output with deeper tones.

Gib

1.
(Half-Life) Short for giblet. Especially, for Half-Life, in description
of fragmented body parts.

Hall of Mirrors

[popupid: hall_of_mirrors]

1.
(Engine) The name given to a specific effect in the rendering engine, which resembles a
Hall of Mirrors . The effect is caused by an absence of rendering information being
sent to the renderer about a specific area in the frame, which is not updated, leaving the
existing render data in place. Over sucessive frames, this old data builds up on itself
to leave a pixel trail based effect. In Half-Life mapping, the effect is usually
a sign of a greater problem within the map, such as a leak or a leaf portal saw
into leaf compile error.

HINT

1.
(Mapping) The name of a specific texture which allows the creation of
Hint brushes (Link: #Hint Brushes) . This texture is included in the
ZHLT (Link: #_ZHLT) series of compile tools in zhlt.wad.

See Also: Hint Brushes (Link: #Hint Brushes) .

Hint Brushes

[popupid: hint_brush]

1.
(Mapping) A brush textured only with HINT and SKIP textures. The brush
is used to force the compile tools to generate additional BSP splits during the map compile
process.

See Also: Hint Brush Tutorial (Link: index.php?doc=1043477348-95410300) .

Hollow

[popupid: hollow]

1.
(Worldcraft) A tool used to hollow a solid primitive into several smaller primitives.
The tool is accecible via:

• the right-click menu
• the menu item Tools, Make Hollow
• the keyboard shortcut Ctrl+H

From the Worldcraft help file:

The hollow function allows you to take a block and hollow it.

To hollow outward (ie: to make the block the inside area of the hollow cube), use a
negative number for the wall thickness.

Hull

[popupid: hull]

1.
(Mapping) A set of surfaces generated by the compile tools during the map compile process.
There are 4 hulls (stored in hullfiles mapname.p0 thru mapname.p3) generated for any given map.
The first hull (Hull 0) stores all of the visible surfaces in the map, while the remaining three
(Hulls 1 to 3) contain clipnode information for the 3 basic hull sizes.

Keyvalue

[popupid: keyvalue]

1.
(Mapping) A piece of information attached to an Entity (Link: #Entity) . The keyvalue is composed of two
components: A Key , which uniquely identifies the bit of data, and a Value ,
which contains the actual data for that specific key . The value is always dependant
on the key, but the key is never dependant on the value.

An example of a keyvalue for an entity, such as a moving door, may be:

Key: Speed (units per second)

Value: 10

In programming, a pointer to a keyvalue data structure is often abbreviated as PKVD.

Lag

[popupid: lag]

1.
(Gameplay) Used to describe the effects of high latency (Link: #Latency) . These effects
often include 'stuttered' or 'jerky' client (Link: #Client) movement, improper physics, apparent weapon
fire inaccuracies, and other such anomalies.

See Also: Latency (Link: #Latench) .

2.
(Engine) Any sort of apparent sluggishness or slowdown in performance.

Latency

[popupid: latency]

1.
(Engine) The amount of time (often measured in miliseconds) for a single packet of data to traverse
from the Server (Link: #Server) to the Client (Link: #Client) and back to the Server again.
High levels of latency (eg. in the range of 300+ ms) indicate a slow or otherwise poor connection from
the client to the server; low levels (eg. lower than 100 ms) incdicate the opposite.

See Also: Ping (Link: #Ping) .
See Also: Lag (Link: #Lag) .

Leaf

[popupid: leaf]

1.
(Mapping) A 'chunk' of player space within the map which has been assigned surfaces.

Compare: Leafnode (Link: #Leafnode) .

Leafnode

[popupid: leafnode]

1.
(Engine) A node on the end of the node tree in a Binary Space Partition (Link: #Binary Space Partition) file.

Leak

[popupid: leak]

1.
(Mapping) A level design/construction error in the map which occurs when all Point Based Entities (Link: #Point Based Entity) are not enclosed by World Brush (Link: #World Brush) es. This condition is usually
picked up in the BSP (Link: #_BSP) stage of the map compile process. Usual error messages
include LEAK LEAK LEAK and Warning: === LEAK in hull n === depending
on the compiler that you are using.

See Also: Leaks (Link: index.php?go=leaks) .

Model

[popupid: model]

1.
(Engine) An object that is not constructed of brushes, but
modelled triangles loaded from an .mdl file (a format that is
proprietry to Half-Life). Scientists and Apache Helicopters are
examples of engine models. In general, the Half-Life engine
can handle the render of models much better than it can of
brush surfaces. (Note: in r_speeds readouts, the wpoly figure
is a measure of brush surfaces, and epoly a measure of model
triangles.)

2.
(Compile Tools) A Brush Based Entity (Link: #Brush Based Entity) . Not to be confused with
the engine definition of a model, which is in all respects, totally
different.

Noclip

[popupid: noclipping]

1.
(Engine) A Console (Link: #Console) command which is used to
disable player clipping within the map. This has the effect of
allowing the player to 'float' unobstructed anywhere within the map.

Node

1.
(Engine) A branching of the BSP Tree.

NULL

[popupid: null_texture]

1.
(Mapping) A texture used on surfaces within a map which the map designer
does not wish to render when the map is played in the game. The texture is
unique to the ZHLT Custom Build (Link: index.php?go=mhlt) series of map compiling tools.

Taken from the instruction manual:

The NULL texture is one that is removed from the map during compilation,
so that it won't exist when you play the compiled .bsp file in Half-Life. You should
be able to apply it to any entity or world brush within your map. The main point of
this texture is to use it on faces that the player would under normal circumstances
never see, so that those faces will not add to the w_poly count and lower the fps
(frames per second) rate.

See Also: ZHLT Custom Build (Link: index.php?go=mhlt) .

OpenGL

[popupid: opengl]

1.
(Engine) Short for Open Graphics Library, an opensource 3D graphics rendering API
that the Half-Life engine uses in the OpenGL rendermode.

Taken from the OpenGL website:

OpenGL is a cross-platform standard for 3D rendering and 3D hardware acceleration.
The software runtime library ships with all Windows, MacOS, Linux and Unix systems.
OpenGL is the essential 3D library that lets you harness the power of hardware
acceleration to thrust games into the realm of professional-quality rendering,
texture-mapping and special effects. Almost all of the leading games (e.g. Quake III,
Half-Life, MDK2, Baldurs Gate, Decent 3, Madden NFL 2001 etc.) require OpenGL for
hardware acceleration.

See Also: OpenGL homepage (Link: ) .

ORIGIN

1.
(Mapping) The name of the texture used when making an Origin Brush (Link: #Origin Brush) .

See Also: Origin Brush (Link: #Origin Brush) .

Origin Brush

[popupid: origin_brush]

1.
(Mapping) A Brush (Link: #Brush) which is used to describe the origin point of a Brush Based Entity (Link: #Brush Based Entity) .
The Brush must have all Faces (Link: #Face) covered with the ORIGIN Texture (Link: #Texture) found in the
standard halflife.wad file. Each Brush Based Entity has a maximum of one Origin Brush.
The center of the Origin Brush itself is used to mark the center of the Brush Based Entity.

See Also: Using ORIGIN for Rotating Entities (Link: index.php?go=rotating_objects) .

Pantone

1.
(Graphic) The name given to a particular colour model. Each colour has a code, relying on the output device to create
the exact colour. Mostly used in Large scale printing projects where the desginer needs a specific
colour with little error margin.

Compare: RGB (Link: #_RGB) .
Compare: CMY (Link: #_CMY) .

Ping

1.
(Engine) Synonym for Latency (Link: #Latency) .

See Also: Latency (Link: #Latency) .

Pitch

[popupid: pitch]

1.
(Audio) A measure of the degree of highness or lowness
in a particular sound.

2.
(Engine) A measurement of view elevation.See Also: Pitch Roll Yaw (Link: index.php?doc=1045097562-00971300) .

Plane

[popupid: plane]

1.
(Geometry) A flat 2D surface that extends infinately in all directions along i